In the event of a derailment, a railway tank car may be punctured resulting in release of its contents. If the railway tank car is carrying material that is a toxic inhalation hazard (TIH), puncturing the tank car may be dangerous to nearby individuals or the environment. Applying reinforcing steel plates outside of the inner tank shell of a railway tank car may increase the puncture resistance of the car.
During manufacturing, railway tank cars undergo a post-weld heat treatment process after they are welded. This process minimizes stresses that are built up during welding and tempers any Martensite in the weld. When reinforcing steel plates are subjected to this post-weld heat treatment process, their strength properties may degrade.